Two people have died and at least 55 others are injured following an enormous explosion on a highway in Bologna, Italy, according to the ANSA news outlet.

The explosion was heard just before 2pm in the Borgo Panigale area, on the outskirts of the city. There are differing reports regarding the number of people casualties. The Rai news outlet is reporting that as many as 100 people are injured. At least 14 of the injured are in a serious condition.

The blast happened after a truck carrying flammable liquids was involved in a crash with other vehicles. The police shared video footage showing that a large section of the road collapsed following the incident.

The fire then spread to a carpark beneath the overpass, where several other vehicles caught fire and exploded. Several blasts were heard over the course of nearly 10 minutes.

Video footage from the scene shows huge columns of billowing into the air following the blast. Several social media users captured footage of the massive explosion which showed an enormous fireball bursting into the sky.

The explosion was caught on film and posted on Instagram by Bologna resident Michele Palma. It shows a dark column of smoke quickly followed by a violent eruption of flames seemingly filling the entire adjacent street.

The police warned of impaired vision in the vicinity of the fire as plumes of smoke spill into the surrounding area. Several roads have been closed.

Witness Marco Rosadini was in a nearby restaurant when the incident occurred. He told La Repubblica that he initially thought it was an attack.

“With the explosion, the glass roof of the restaurant started to collapse. People started to run away,” he said.

“We were seated, at one point there was a very loud explosion and everything started to come down in. I looked outside and it seemed to me [there was] a whole wall of flames. There were seven to eight minutes of explosions: I did not really think about an accident, I had thought about an attack.”

Deputy Prime Minister Matteo Salvini paid tribute to the emergency services that responded to the blast.

“My thoughts are with the victims and the injured of the terrible explosion of Borgo Panigale, and a heartfelt thanks to the 100 firefighters who promptly intervened on the spot,” he wrote on Facebook.